1. Field of the Invention
The present invention relates to a sorter, in detail, a sorter which sorts sheets discharged by an image forming apparatus such as an electrophotographic copier, laser printer and the like to a plurality of bins.
2. Background of the Invention
Recently sorters of the above-mentioned type have been provided which are capable of not only sorting sheets but also stapling or punching sheets or the like. In the process of stapling sheets, it is required to align the sheets accommodated in each bin to a predetermined position in advance. Conventionally a sheet aligning system has been proposed which comprises a pivotable aligning rod penetrating all bins to press the sheets accommodated in each bin to an alignment reference plate thereby. Further, a system has also been proposed which rotates a paddle wheel comprising elastic blades in one direction to align sheets at an aligning corner on a tray.
However, the sheet aligning system with the alignment rod may cause poor alignment when the sheets are curled and thus includes a problem of lacking reliability. Further, it is required to control a pivotal stroke of the alignment rod to be changeable in accordance with sheet size.
On the other hand, the system with a paddle wheel is, in case of being applied to a sorter which sorts sheets to a plurality of bins, required to be provided on each bin. This causes a complication of structure of an apparatus and inefficiency of space.